/*
 * Copyright (c) 2001, 2003, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */
package com.sun.jmx.snmp;


import java.io.Serializable;
import java.net.InetAddress;

/**
 * Is the fully decoded representation of an SNMP packet.
 * <P>
 * Classes are derived from <CODE>SnmpPdu</CODE> to
 * represent the different forms of SNMP packets
 * ({@link com.sun.jmx.snmp.SnmpPduPacket SnmpPduPacket},
 * {@link com.sun.jmx.snmp.SnmpScopedPduPacket SnmpScopedPduPacket})
 * <BR>The <CODE>SnmpPdu</CODE> class defines the attributes
 * common to every form of SNMP packets.
 *
 *
 * <p><b>This API is a Sun Microsystems internal API  and is subject
 * to change without notice.</b></p>
 *
 * @see SnmpMessage
 * @see SnmpPduFactory
 * @since 1.5
 */
public abstract class SnmpPdu implements SnmpDefinitions, Serializable {

  /**
   * PDU type. Types are defined in
   * {@link com.sun.jmx.snmp.SnmpDefinitions SnmpDefinitions}.
   *
   * @serial
   */
  public int type = 0;

  /**
   * Protocol version. Versions are defined in
   * {@link com.sun.jmx.snmp.SnmpDefinitions SnmpDefinitions}.
   *
   * @serial
   */
  public int version = 0;

  /**
   * List of variables.
   *
   * @serial
   */
  public SnmpVarBind[] varBindList;


  /**
   * Request identifier.
   * Note that this field is not used by <CODE>SnmpPduTrap</CODE>.
   *
   * @serial
   */
  public int requestId = 0;

  /**
   * Source or destination address.
   * <P>For an incoming PDU it's the source.
   * <BR>For an outgoing PDU it's the destination.
   *
   * @serial
   */
  public InetAddress address;

  /**
   * Source or destination port.
   * <P>For an incoming PDU it's the source.
   * <BR>For an outgoing PDU it's the destination.
   *
   * @serial
   */
  public int port = 0;

  /**
   * Returns the <CODE>String</CODE> representation of a PDU type.
   * For instance, if the PDU type is <CODE>SnmpDefinitions.pduGetRequestPdu</CODE>,
   * the method will return "SnmpGet".
   *
   * @param cmd The integer representation of the PDU type.
   * @return The <CODE>String</CODE> representation of the PDU type.
   */
  public static String pduTypeToString(int cmd) {
    switch (cmd) {
      case pduGetRequestPdu:
        return "SnmpGet";
      case pduGetNextRequestPdu:
        return "SnmpGetNext";
      case pduWalkRequest:
        return "SnmpWalk(*)";
      case pduSetRequestPdu:
        return "SnmpSet";
      case pduGetResponsePdu:
        return "SnmpResponse";
      case pduV1TrapPdu:
        return "SnmpV1Trap";
      case pduV2TrapPdu:
        return "SnmpV2Trap";
      case pduGetBulkRequestPdu:
        return "SnmpGetBulk";
      case pduInformRequestPdu:
        return "SnmpInform";
    }
    return "Unknown Command = " + cmd;
  }
}
